Sugar additions don't need to be added during the boil and they may be better added during fermentation.

What a lot of Belgian-style brewers do, to avoid over-burdening the yeast at the beginning of fermentation and prevent the yeast from stalling after fermenting the simple sugars, is to make sugar additions directly to the fermenter as the fermentation slows down. You can boil and chill the sugar addition, or just add it dry, with relatively little risk.